Voltage drop is terrible after adding more batteries. :/

[lnsomnia]

Hey guys! So I just recently added four deka 105ah batteries and before that I only had my xs battery up front and a yellow top in the back to power an saz-2500 and a small infinity amp with my 140amp alternator.

I was originally dropping down to about 11.6-11.8

Now I'm dropping all the way down to 10.8-10.9.

Prior to putting the batteries in they were all given a full charge and load tested. Each battery was rated good.

Why am I dropping so low? Ideas? Suggestions?

Thanks!

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[fatboytyler]

Double check all the wiring. Also have you done the Big 3? And it's possible that the alternator doesn't have enough juice to recharge that many batteries that quick, but I do not know for sure.

 

[lnsomnia]

Double check all the wiring. Also have you done the Big 3? And it's possible that the alternator doesn't have enough juice to recharge that many batteries that quick, but I do not know for sure.

Yes I've done the big 3. I'll double check the wiring later but they should be fine. I just used aluminum bus bars to connect them all together and wired pos/neg like normal. I'm getting a new alternator soon but I figured the batteries should be holding some sort of a charge and not act as if they're completely drained on my volt meter.

 

[will3 10+ year member]

What are you grounded to an how ? size wire etc.

 

[72Impala 10+ year member]

Still using the same amplifiers? I know it sounds like a dumb question. Also, did you change the ground location of your amplifiers? If they went to the rear batteries before, do the same again.

 

[shizzzon 10+ year member]

XS, Optima and Deka batteries that are not intended for car audio use..

You have 3 different batteries in your car fighting with each other.

You are mixing too many technologies together just bleeding each other down.

 

[boxpunch]

XS, Optima and Deka batteries that are not intended for car audio use..
You have 3 different batteries in your car fighting with each other.

You are mixing too many technologies together just bleeding each other down.

Huh? Only 2 types of batteries (gel and agm). The deka's (if 8a31 or 9a31) are an agm battery that's built for high current draw in bursts, that would be good for car audio.

Back to the OP, when is the last time you charged your batteries (have you charged them since noticing voltage drop?)

Your connections are secure and clean?

Your amps are grounded to the rear batteries and rear batteries grounded to the frame of the car?(or a solid bolt on the body, if it's a unibody vehicle)

You've got what size (and brand) wire running to the rear?

Your voltmeter is pulling voltage from the amp or the front of the car?

 

[disturbed471985 5,000+ posts]

That's a lot of batt to charge..

 

[shizzzon 10+ year member]

There are two different kinds of AGM, High Rate and Deep Cycle and you have Gel..

XS is High Rate

Optima.. it's a mix of everything. Even dealers do not know what to believe from them anymore.

Deka- It's either an 8a31 or 9a95. In either case, not a High Rate AGM like the XS is.

Just because they float the same doesn't mean they won't fight with each other. Different chemistry's of AGMs will still fight with each other.

 

[mlstrass 5,000+ posts]

I've used mixed batteries numerous times, AGM & reg lead acid, or several diff brands of AGM. Never had an issue.

Either you have a bad connection/ground or one of the batts has some dead cells....

 

[lnsomnia]

I know I'm a bit late on replying but I would like to verify that I'm only using two different a kinds of batteries; the XS up front and the Dekas in the back. In the OP I stated that the Optima is what I used to have in the back until I replaced it with the Dekas.

They are grounded to the bare metal of the car where my spare tire used to be.

 

[los33]

Have you tried using a DMM to check the current on all the batteries?

Maybe a single bad battery could be draining the rest.... Just because you tested them does not mean it couldnt have gone bad due to battery mixture.

 

[audiobaun 5,000+ posts]

Ive always used OFC 0ga wire with copper ring terminals..Ive never felt that aluminum is really a great conductive source for any power connection.If you could draw a diagram of how you have your wiring routed,as well as grounded,and size of wiring,and take a pic of your diagram post it here,maybe there might be an issue with the way you have wired it/grounded ect?Be easier to view/understand a bit better of what you have going on..Sounds like to me..you need a bigger alt.to charge 5 battseries.140 isn't going to get it done man.That internal regulator is going to Fry its azz off,working that hard..Just my 2 centsTakes power to make power,and power to maintain power.

 

[audiobaun 5,000+ posts]

Id try to leave the XS under the hood, and run two Dekas..see how well that works for you,rather than 4 Dekas..Should charge better with that sized alt,possibly stay within the 11.9-12.6 range

 

[big bass joel 10+ year member]

he can also run a 0 gauge negative run from front battery to the rear deka batteries.